Inverter-integrated electric compressors, which integrally incorporate inverter devices, are used as air conditioner compressors installed in electric vehicles, hybrid vehicles, and the like. This inverter-integrated electric compressor is configured so that high voltage direct current power supplied from a power supply unit installed in a vehicle is converted to three-phase alternating current power of a required frequency in an inverter device, which is then applied to the electric motor so that the electric motor is driven.
The inverter device is configured by a plurality of high-voltage electrical components such as a coil and a capacitor configuring a filter circuit for noise removal, a plurality of semiconductor switching elements such as IGBTs configuring a switching circuit for converting electric power, a circuit board on which an inverter circuit including the filter circuit and the switching circuit, or a control circuit thereof, is mounted, and the like. The inverter device is integrated by being incorporated into an inverter housing section provided on the outer periphery of the housing of the electric compressor.
Patent Document 1 discloses an invention with a configuration in which a control circuit board mounted with a capacitor or a microcomputer, an inverter circuit board mounted with an IGBT, or a circuit board integrating these two circuit boards is installed in a circuit casing on a housing side via a large number of columnar legs and heat generated by heat generating components is dissipated through the legs. Patent Document 2 discloses an invention with a configuration in which a power conversion circuit board mounted with a switching element, a capacitor, a coil, or the like is installed via an elastic member on a circuit board cover side, the circuit board cover is attached to an inverter installation surface on the housing side, a fluid member such as a gel material is arranged between each of the electrical components and the facing surface and a concave section on the installation surface side, whereby gaps are adjusted and the heat radiation property is secured.
Furthermore, Patent Document 3 discloses an invention in which an inverter circuit board is divided into two of a power system circuit board mounted with a switching element and a CPU circuit board mounted with a control circuit and integrated as a module via a case made of resin, the switching element is sealed with a thermosetting resin layer, and a silicon based elastic adhesive layer is provided between the thermosetting resin layer and the CPU circuit board, whereby the vibration resistance is secured.